Delhi chilly again as minimum drops below 5°C for 3rd time this month

NEW DELHI: The Capital has recorded its cleanest first half of December ever since the compilation of air quality index (AQI) started in 2015, recording just one "very poor" air day in the first half of the month and no "severe" air day, according to the Central Pollution Control Board (CPCB) data.

- Jasjeev Gandhiok

Besides, there were six "moderate" air days, which is also the highest number for December, and eight "poor" air days, according to CPCB.

Delhi's average AQI between December 1 and December 15 this year was 238, the lowest ever for December. Over the past nine years, the average AQI in the first half of December has been over 300, making this a significantly cleaner first half of the month.

Before this, the lowest average AQI in the first half of the month was 301, in 2022. The average AQI for the corresponding period last year was 327.

To be sure, there has been no "good" or "satisfactory" air day recorded in December since data collection started.

Meteorological experts said strong and consistent winds have been recorded across northwest India all through the month, with a lack of moisture and fog further helping improve the air quality. "Generally in December, we see moderate to dense fog, which makes dispersion of pollutants difficult. At the same time, winds are also slow. On average, winds have been (blowing at speeds of) over 8-10km/hr on most days, with this regularly touching 20km/hr on multiple days," said Mahesh Palawat, vice president at Skymet meteorology.

He said that Delhi-NCR has recorded clear skies on most days. "There has not been enough moisture in the plains, barring a few days. This meant fog is not forming with the same intensity it was seen in mid-November," he said.

The average AQIs between December 1 and 15 over the previous years were 322 in 2021, 335 in 2020, 321 in 2019, 330 in 2018, 304 in 2017, 367 in 2016 and 323 in 2015.